In a molding process, die lock situations are commonly associated with the manufacture of assemblies having a complex internal geometry. A die lock refers to the situation where the geometry of one part in an assembly creates an interference in the mold with other parts of the same assembly that cannot be overcome by utilizing a slide or a core pull.
A typical solution to the above problem is to form the parts in a die lock situation separately before connecting them to obtain the assembly with the required configuration. Such additional processes not only increase manufacturing costs but also decrease product quality at the conjunction of the constituent parts. Another solution to avoid a die lock situation is redesigning such assemblies to other patterns with no die lock configurations. However, such changes usually result in more complicated designs of the assemblies which increase manufacturing costs.
Fusible cores have been adopted in molding processes to form any interior geometry of an assembly. A fusible core is a solid and dimensionally accurate metal insert having a low melting point. This fusible core is melted and removed after the formation of the assembly leaving behind the required interior geometry. However, due to the large amount of heat produced in the process of melting the core material, defects, such as deformation, cracks, etc., are usually formed on the finished surfaces of the assembly, thus affecting the quality of the finished surfaces.
It is therefore advantageous to obtain a molding process in which different parts of a die lock situation can be integrally formed in a single molding step. It is also advantageous to obtain a molding process which can not only produce an assembly having surfaces in die lock situations with its main body but also provide an accurate and defect-free finish to such surfaces.